In the field of automotive engineering the document EP 0 987 389 in the name of the Applicant company, for example, discloses key casings comprising an electronic part used to identify a user of the vehicle through the exchange of electromagnetic signals, and a mechanical part containing a back-up key.
Such casings are particularly practical because they allow the key to be concealed within the actual structure of the casing which protects it. This is highly advantageous because the user needs this back-up key only in the event of an electrical failure, for example if the battery in the electronic part is dead or the vehicle battery fails.
This arrangement also prevents the key insert from catching in the user's pockets and damaging his or her clothing. This arrangement furthermore allows the size of the casing to be reduced significantly.
In the above-mentioned document EP 0 987 389, the back-up key comprises a bow part forming a part for holding and a metal insert which can be used as a back-up mechanical key, the bow part being fixed rigidly perpendicular to the metal insert.
In order to accommodate this back-up key, the casing comprises, along one of its edges, a housing forming a sleeve intended to accommodate the insert and the bow part of the key is clipped onto a corresponding opening of the casing.
However, given that the number of functions performed by the electronic part is constantly increasing, entailing more numerous electronic components, it is necessary to reduce the size of the back-up insert as far as possible.
Additionally, given that there is no hermetic separation between the electronic part and the mechanical part, special-purpose sealing means needs to be provided, and this tends to increase the cost of the casing.
The present invention aims to alleviate these various disadvantages by proposing a key casing comprising a key, particularly a back-up key, having a smaller size.